You don’t say how he is mentally, how unwell he is or how he responds on your visits, but it does sound as if he would be very much better off in a Nursing home. With pressure sores, eating and drinking problems he’s likely to be in need of much more input than he would receive in a Care Home.
You should be able to see if he’s just unhappy and this has affected his interest in eating properly. No, he cannot be forced to eat but he’s unlikely to benefit from just being offered a meal on a tray and rather left to his own devices and this might have been the case in a hospital or Care home situation. He possibly does need to spend some time with further tests in hospital and medical assessments, but unless he shows a huge improvement on discharge, it would make much more sense if he is then moved to a Nursing home and you spend a lot more time with him there - particularly at meal times. If you take in home-cooked treats, things that will tempt him and will put on weight, so that he can eat little but often, it’s possible his appetite will return. And use a small, coloured plate or dish!
All the other ‘heavy’ work and nursing care is best left to those employed to do just that. All the time spent on turning him, bathing him, changing bedding, etc., is not something you should want to wear yourself out on when you can cook for him, feed him, spend time and cheer him, because this will take the pressure off you and a lot of the responsibility. Try to make it easier on both of you. Good luck and I hope your care and input will make a difference.